When I was developing the precision survey code for Lady Heather, I used a lot of antennas. My definition of antenna quality boiled down to how well the results of a 48 hour survey compared to the cm level survey point that I had for my antenna position (from a Ashtech Z12 receiver / matched choke ring antenna). One thing you can try is running Lady Heather with various antennas with the receiver in 3D positioning mode and enabling the lat/lon "scattergram" display (G I command in the next release). This will produce an X-Y plot of fixes from the point when the display was enabled. Better antennas will produce "tighter" scattergrams. Another thing to try is running Lady Heather's precision survey command. This will display the scattergram and also write all the position fix data to the file "lla.lla" that you can process as you see fit. Also, the next version of Lady Heather can write GPX, XML and KML format log files that have the lat/lon/alt info in them.

On 11/20/16 7:41 PM, Mark Sims wrote: > When I was developing the precision survey code for Lady Heather, I > used a lot of antennas. My definition of antenna quality boiled down > to how well the results of a 48 hour survey compared to the cm level > survey point that I had for my antenna position (from a Ashtech Z12 > receiver / matched choke ring antenna). > This is similar to the UNAVCO evaluaton approach http://kb.unavco.org/kb/article/unavco-resources-gnss-antennas-458.html "Antenna phase center variations can be characterized by mean phase center offsets and by phase and amplitude patterns for L1, L2 and L3 (ionosphere free combination) tracking as a function of azimuth and angle. Mean offsets are defined as the average phase center locations relative to a physical reference point on the antennas (typically the base of the antenna preamplifier as used in RINEX files). The patterns are defined as the azimuth and elevation dependence to be added to the average phase center offsets. The sum of the mean phase offset and pattern gives the signal path delay for a given satellite elevation and azimuth. Precise knowledge of these phase patterns is essential for mixing antennas of different design where uncorrected effects can be as large as 10 cm in the vertical and 1 cm in the horizontal baseline components. The effect is more subtle for antennas of the same design. Here the problems arise over long baselines where the same satellite is observed at different relative directions and therefore experiences different delays at each site which can introduce solution scale errors. In addition, there is the issue of consistency of the phase patterns and offsets for each individual antenna of the same design."